The present invention relates to an alkaline dry battery, and more particularly to a separator to be disposed between a positive electrode and a negative electrode.
Conventionally, the physical properties of a separator for use in an alkaline dry battery has been evaluated primarily in the form of a separator base paper in a dry condition before the battery is assembled. It has been proposed, for example, for a separator base paper rolled into a hoop shape, that the ratio of the tensile strength in the longitudinal direction to the tensile strength in the width direction be set within a range of 1:1 to 2:1 (refer, for example, to Japanese Unexamined Patent Publication No. 2000-90939).
However, the strength of the separator in a wet condition after assembled in the battery, in particular, the strength of the separator impregnated with an alkaline electrolyte, differs from the strength of the separator in a dry condition. Therefore, it does not necessarily follow that the separator having high strength in a dry condition has excellent drop impact resistance.